1. Field of the Invention
The present invention relates to an airbag curtain positioning system and method. More specifically, the present invention relates to a system and a method for positioning an airbag curtain at a desired location relative to an airbag inflator during attachment of the curtain to the inflator.
2. Technical Background
Inflatable airbags are well accepted in their use in motor vehicles and have been credited with preventing numerous deaths and accidents. Some statistics estimate that frontal airbags reduce fatalities in head-on collisions by 25% among drivers using seat belts and by more than 30% among unbelted drivers. Statistics further suggest that with a combination of seat belt and airbag, serious chest injuries in frontal collisions can be reduced by 65% and serious head injuries by up to 75%. Thus, airbag use presents clear benefits.
Airbags may be positioned in a variety of locations throughout the vehicle. Airbags located within the steering wheel aid in preventing the driver from striking the steering wheel and the windshield in the event of an accident. Airbags have also been placed in the dashboard directly in front of the passenger seat in a vehicle. Knee bags have also been created to prevent an occupant""s lower body from striking the vehicle. More recently, airbags have been installed on the interior sides of a vehicle to prevent occupants from striking the doors and windows of the vehicle during an accident. This type of airbag is frequently referred to as an inflatable curtain.
Previously, sensors were placed in a vehicle""s bumpers to determine when to deploy the airbag curtain. A modem airbag curtain apparatus, however, may include an electronic control unit (ECU). The ECU is usually installed in the middle of an automobile, between the passenger and engine compartment. The ECU includes a sensor that continuously monitors the acceleration and deceleration of the vehicle. The ECU sends this information to a processor that analyzes the information with an algorithm to determine whether the vehicle is in an accident.
When the processor determines that there is an accident situation, the ECU transmits an electrical signal to an initiator in, for example, an airbag curtain module. The initiator triggers operation of the inflator. The inflator inflates a textile airbag curtain to prevent injury to the passenger. In some airbag apparatuses, the airbag may be fully inflated within 50 thousands of a second and deflated within two tenths of a second. Tremendous force is required to inflate the airbag so quickly.
Airbag inflators come in a number of different varieties. Some inflators, which are often referred to as xe2x80x9cstored gas inflators,xe2x80x9d simply store the gas in a high-pressure state and release the gas during an impact. xe2x80x9cPyrotechnicxe2x80x9d inflators, by contrast, do not store gas; rather, they contain propellants that, upon ignition, react to produce the gas. xe2x80x9cHybridxe2x80x9d inflators utilize compressed gas in combination with pyrotechnics to produce the gas. In some instances, the pyrotechnic can also open or rupture a chamber containing pressurized gases, allowing the pressurized gas to escape and inflate into an attached airbag. Whatever the type of inflator, tremendous pressure and heat are generated at the moment of impact.
Because of the tremendous stress placed on an inflatable curtain and inflator during an accident, correctly assembling and installing these items is critical to avoid product failure or costly reinstallation procedures. During the manufacturing process, an inflatable curtain is often attached to an inflator using a clamp. If the inflatable curtain is not correctly positioned relative to the inflator when it is clamped to the inflator, serious consequences can result. For example, inflatable curtains are often installed just above a door to a vehicle and, in an accident, deploy in an outward and/or downward direction to prevent the occupants from striking the door or window. Thus, an inflatable curtain is generally not symmetrical and involves an angle of deployment. An inflatable curtain, as a consequence, could be improperly installed and deploy into the ceiling of the vehicle, failing to prevent an occupant from striking a side door or window. Also, if an inflatable curtain is not correctly positioned relative to the inflator, the airbag curtain may be twisted during installation and rip or otherwise fail to correctly deploy.
Also, an airbag curtain should be correctly positioned along the longitudinal axis of the inflator. If there is too much overlap or too little overlap between the airbag curtain and the inflator, problems may arise. For instance, if there is too little overlap, leaks may allow inflator gas to escape during inflation. It is even possible that the extreme force of deployment may cause the curtain to separate from the inflator. If there is too much overlap, the clamp may bind a portion of the airbag curtain that was designed to expand during inflation, again preventing correct deployment.
To further exacerbate the situation, assembly-line workers attach the inflatable curtain to the inflator when the curtain is in a folded state, making it even more difficult to determine how the curtain should be oriented with respect to the inflator. Additionally, these workers are often presented with a very short period of time to perform this repetitive operation, increasing the possibility of human error.
Thus, it would be an advancement in the art if a method and system could be developed that quickly and easily indicates to an assembly-line worker when an inflatable curtain is correctly positioned relative to an inflator. It would be a further advancement if such a system could ensure correct positioning of the inflatable curtain along a longitudinal axis of the inflator. It would also be beneficial if such a system and method could ensure that the angle of deployment of an airbag curtain is correctly positioned relative to the inflator. This advancement would significantly be enhanced if implemented in a cost-effective manner.
Such a device is disclosed and claimed herein.
The apparatus and methods of the present invention have been developed in response to the present state-of-the-art, and, in particular, in response to problems and needs in the art that have not yet been fully resolved by currently available airbag curtain inflator systems. The present invention provides an apparatus for enhancing the effectiveness of airbag curtain inflator systems. To achieve the foregoing, and in accordance with the invention as embodied and broadly described in the preferred embodiment, an airbag curtain inflator system that diminishes the risk of improper attachment of an inflator to an airbag curtain is disclosed.
The inflatable curtain positioning system of the present invention may include a curtain inflator and an inflatable curtain. The inflator generates inflator gas for inflating the curtain. To accomplish this, the curtain inflator may implement, for example, compressed gas, pyrotechnic, or hybrid techniques, as discussed above.
The inflator may include a housing having a neck. The neck is designed to receive the inflatable curtain.
A protrusion is disposed on the neck. The protrusion may be embodied in various forms, such as a hook or a tab. The inflator may have a proximal end (an end closest to the inflatable curtain) and a distal end. In one implementation, a hook curves toward the distal end of the inflator.
In one embodiment, the inflator does not include an outer protective housing. Thus, one or more of the protrusions may be disposed directly on the inflator, not the housing.
Alternatively, the tab may project in a generally perpendicular direction away from the surface of the housing. Naturally, a tab may be shaped in a variety of different ways such that the tab has, for example, a circular-, square-, or rectangular-shaped intersection with the housing.
The inflatable curtain includes a throat configured to be disposed around the neck of the inflator. An opening is disposed within the throat. The opening may be configured to receive the protrusion only when the curtain is positioned at a desired location relative to the housing.
Positioning the curtain relative to the housing involves at least two variables. First, the curtain may be positioned at a desired location along a longitudinal axis of the housing. If there is too little overlap between the curtain and the longitudinal axis of the housing, the seal between the inflator and curtain may not be airtight, allowing inflator gas to escape during inflation. It is even possible that the extreme force of deployment may cause the curtain to separate from the inflator, if the overlap is inadequate. If there is too much overlap, the clamp (which secures the curtain to the housing) may bind a portion of the curtain that was designed to expand during inflation.
Second, an inflatable curtain is generally not symmetrical and involves an angle of deployment. The angle of deployment is the direction in which the curtain inflates in the event of an accident. As a consequence, an inflatable curtain may be improperly installed and deploy, for example, into the ceiling of the vehicle, failing to protect an occupant. Additionally, if an inflatable curtain is not correctly positioned relative to the housing the airbag curtain may be twisted during installation and rip or otherwise fail to correctly deploy when inflated.
To assemble an inflatable curtain system of the present invention, a worker positions the neck of the inflator within the throat of the curtain. The worker then places the curtain on the housing such that the protrusion is positioned within the opening. Thereafter, a clamp may be used to secure the curtain to the housing. Thus, assembly is simple and virtually eliminates positioning errors present in conventional systems. More particularly, the opening may be manufactured to receive the protrusion only when the curtain is positioned at a desired location along the longitudinal axis of the housing and when the angle of deployment of the curtain is at a desired location relative to the housing
The clamp may secure the curtain to the inflator. The clamp may be embodied in various forms, including, for example, a hose clamp or ring.
In one alternative design, at least two protrusions are disposed on the housing and mating openings are disposed within the throat of the curtain. The protrusions and mating openings may be placed at irregularly spaced intervals along the perimeter of the housing, such that each protrusion fits within mating openings only when the curtain is positioned at a desired location relative to the housing.
This invention presents a significant advancement in the art in that it provides an assembly-line worker with clear, easy-to-follow guidance in positioning an inflator relative to a curtain during assembly. More particularly, when the present invention includes either one opening and one protrusion or a plurality of irregularly spaced protrusions and a plurality of mating openings, the inflatable curtain positioning system provides an assembly-line worker with essentially only one way of positioning the inflator relative to the curtain. Conventional airbag curtain systems provide little or no guidance to an assembly-line worker for positioning these two items, resulting in potentially dangerous and/or costly errors. As a consequence, the present invention may decrease training and quality control costs.
These and other advantages of the present invention will become more fully apparent from the following description and appended claims, or maybe learned by the practice of the invention as set forth hereinafter.